style: align string/base/trim with namespace conventions

Added missing `base` keyword (present in 78% of `string/base/*` siblings).

Author: claude

lib/node_modules/@stdlib/string/base/trim/package.json

@@ -55,6 +55,7 @@
     "utility",
     "utils",
     "util",
+    "base",
     "string",
     "str",
     "whitespace",